1. Field of the Invention
The present invention relates to a surface discharge type plasma display panel and its manufacturing method, and a surface discharge type plasma display device. Especially, the present invention is directed to a structure of barrier ribs and a technique for forming the barrier ribs.
2. Background of the Invention
FIG. 60 is a block diagram showing a plasma display panel device , for example, as disclosed in FIG. 1 of Japanese Patent Laid-Open Gazette P5-307935A or in FIG. 14 of U. S. Pat. No. 5,661,500. In FIG. 60, the reference character 100P indicates a plasma display device; 1P indicates a plasma display panel (hereinafter referred to as a PDP) including X and Y display electrodes (hereinafter referred to as X and Y electrodes, respectively) and an address electrode (hereinafter referred to as an A electrode); 110P indicates a scan control portion; 120P indicates an A/D converter for converting an input signal from analog to digital (hereinafter referred to as an A/D); 130P indicates a frame memory for storing an output of the A/D 120P; 141P indicates an X-electrode driving circuit for providing a driving signal to the X electrode of the PDP 1P; 142P indicates a Y-electrode driving circuit for providing a driving signal to the Y electrode of the PDP 1P; 143P indicates an A-electrode driving circuit for providing a driving signal to the A electrode of the PDP 1P. The reference character 2P indicates a drive control system consisting of the A/D 120P, the frame memory 130P, the scan control portion 1110P, the X-electrode driving circuit 141P, the Y-electrode driving circuit 142P, and ace A-electrode driving circuit 143P
FIG. 61 is a perspective view showing the outline of a sectional structure of the conventional PDP 1P, for example, as disclosed in FIG. 3 of Japanese Patent Laid-Open Gazette No. P5-299019A or in FIG. 2 of U.S. Pat. No. 5,661,500. In FIG. 61, the reference numeral 211 indicates a first substrate which is a front substrate; 217 indicates a dielectric layer covering the X and Y electrodes; 218 indicates a protective layer formed of MgO or the like, for covering the surface of the dielectric layer 217; 222 indicates an A electrode extending along a second direction orthogonal to a first direction which will be described later; 221 indicates a second substrate which is a rear substrate; 228 indicates a phosphor formed in stripes along side walls of barrier ribs 229 which will be described later, without interruption; 229 indicates a barrier rib formed in parallel along the second direction on the second substrate 221 and separated from each other, and 230 indicates a discharge space filled with discharge gas (Penning gas) including Xe atoms for emitting ultraviolet rays to be absorbed into the phosphors 228. Further, 241 indicates a strip transparent conductive film consisting of a tin oxide film or the like, and extending in parallel along the first direction at a predetermined interval (discharge gap) so as to constitute X and Y electrodes XEP and YEP; and 242 indicates a strip metal film for supplementing conductivity of the strip transparent conductive film 241, consisting of multiple films such as Crxe2x80x94Cuxe2x80x94Cr or Crxe2x80x94Alxe2x80x94Cr. Each of the X and Y electrodes XEP and YEP consists of the strip transparent conductive film 241 and the strip metal film 242 added to the strip transparent conductive film 241. The reference character EGP indicates one pixel consisting of three unit luminescent areas EUP emitting red light (R), green light (G), and blue light (B), respectively, (indicated by EUPR, EUPG, EUPB, respectively, in FIG. 61) for a color display device. The reference character SP indicates a display surface.
Next, operation of the conventional plasma display device 100P will be described. The plasma display device 100P consists of the PDP 1P, and the drive control system 2P electrically connected to the X, Y, and A electrodes of the PDP 1P via a flexible printed circuit board (not shown).
In the drive control system 2P, an input signal VINP for providing image data is first converted from analog to digital by the A/D 120P, and digital data outputted from the A/D 120P is stored into the frame memory 130P. Then, the scan control portion 110P accesses the digital image signals stored in the frame memory 130P, and on the basis of the signals, outputs various control signals for controlling drive of the X-electrode driving circuit 141P, the Y-electrode driving circuit 142P, and the A-electrode driving circuit 143P to the corresponding circuits 141P to 143P, respectively. Upon receipt of the control signals, the driving circuits 141P to 143P apply driving pulse signals such as priming pulses, write pulses, or discharge sustain pulses to their corresponding electrodes, which drives the PDP 1P.
The PDP 1P is a three-electrode, surface discharge type PDP where a pair of display electrodes (the X and Y electrodes XEP and YEP) and the A electrode 222 correspond to the unit luminescent areas EU, respectively. Each of the X and Y electrodes XEP and YEP consists of the strip transparent conductive film 241 and the strip metal film 242, and it is arranged on the inside surface of the first substrate 211 on the side of the display surface SP.
On the other hand, the barrier ribs 229 are provided in strips on the second substrate 211. A height h of the barrier ribs 229 specifies a height of the dicharge space 230. The discharge space 230 is sectioned per unit luminescent area EUP along an extending direction of the X and Y electrodes XEP and YEP, that is, along the first direction.
On the inside surface of the second substrate 221 between the adjacent barrier ribs 229 formed in parallel with each other, the A electrodes 222 of a predetermined width are arranged by printing and firing a pattern of a silver paste. Further, except where the barrier ribs 229 are in contact with the protective layer 218 and its vicinity, the phosphors 228 emitting red light R, green light G, blue light B, respectively are provided so as to cover the inside surface of the second substrate 221.
Accordingly, in the PDP 1P, the continuous stripe phosphors 228 are provided almost on the whole inside surface of the second substrate 221 including both side surfaces of the barrier ribs 229 and the surface of the A electrodes 222.
Further, in some cases, a layer (black stripe) using a low melting point glass with a black pigment added, for example, may be provided on the inside surface of the first substrate 211 in order to prevent deterioration in image contrast due to extraneous light entering from outside through the first substrate 211 forming the display surface SP.
The aforementioned conventional technique, however, contains some problems. For easy understanding of one of those problems, a logic of phenomena of the discharge and the propagation of ultraviolet rays will be described schematically with reference to FIG. 62.
On occurrence of discharge (especially display discharge) between the X and Y electrodes, Xe atoms included In discharge gas are excited and emit 147 nm ultraviolet rays. This emission of ultraviolet rays occurs when Xe atoms of resonance level return to their ground level, accompanied with what is called xe2x80x9cself absorptionxe2x80x9d. The xe2x80x9cself absorptionxe2x80x9d is a phenomenon that the ultraviolet rays once emitted from the Xe atoms are absorbed by different Xe atoms being at a ground level, and the different Xe atoms are excited.
These excited different Xe atoms will also emit ultraviolet rays of the same wavelength when returning to their ground level. By repeating the self absorption and the emission of ultraviolet rays in this way, the 147 nm ultraviolet rays propagate and diffuse at random within the discharge space. FIGS. 62A and 62B schematically show this self absorption of ultraviolet rays.
Since the ultraviolet rays propagate and diffuse within the discharge space as described above, the expansion of ultraviolet rays due to the gas discharge between the X and Y electrodes far more reaches than both physical widths of the X and Y electrodes. FIG. 63A schematically shows the expansion of ultraviolet rays when gas discharge occurs between any X and Y electrodes XEP and YEP located in an upper portion of the space which extends along the second direction and is surrounded by the adjacent barrier ribs 229, the phosphors 228, and the protective layer 218 as described above. Further, FIG. 63B schematically shows luminance on the side of the first substrate 211 at that time, where the horizontal axis indicates a distance from the center of discharge gap (substantially corresponding to the center of a display line D).
The discharge between the X and Y electrodes XEP and YEP generates ultraviolet rays as described above, and the ultraviolet rays are propagated and diffused by the self absorption and emission- In this case, since the adjacent barrier ribs 229 are in parallel with each other as shown in FIG. 61, the occurrence of the gas discharge is spatially limited only in the second direction along the A electrode 222. Thus, as schematically shown in FIG. 63B, the distribution of luminance extends along the second direction. The metal electrodes 242, however, do not transmit light from the phosphors 228, so that the display light can not propagate to an area positioned right over the metal electrodes 242. Thus, the distribution of luminance to be observed breaks at positions corresponding to places where the metal electrodes 242 are formed.
A correlation between gas discharge and luminescence state will be further described with reference to FIG. 64. FIG. 64 is a plan view schematically showing the positioning of each unit luminescent area EUP, the barrier ribs 229, and the phosphors 228. In FIG. 64, the phosphors emitting red light R, green light G, and blue light B are denoted by the reference characters 228R, 228G, and 228B, respectively.
As shown in FIGS. 63A and 63B, on the occurrence of the gas discharge between the X and Y electrodes XEP and YEP, the Xe atoms included in the discharge gas are excited and emit ultraviolet rays. The ultraviolet rays are incident on the facing phosphors 228, which causes luminescence (generation of visible light) from the phosphors 228. The phosphors 228 themselves are almost white against the visible light, so that the visible light is hardly absorbed by the phosphors 228. Thus, luminescence emitted from the phosphors 228 is reflected on the surface of the phosphors 228. The barrier ribs 229 also consist of materials for reflecting luminescence. The emitted luminescence does not leak into the unit luminescent areas EUP adjacent to each other with respect to the first direction D1 and emitting luminescence of different colors, because the phosphors 228 are provided in generally U-shaped consecutive stripes along the second direction D2 and the adjacent barrier ribs 229 extending along the first direction D1 prevents the phosphors 228 from emitting in the first direction D1. However, the emitted visible light reflects on the surface of the phosphors 228, and consequently leaks into the unit luminescent areas EUP adjacent to each other with respect to the second direction D. and emitting luminescence of the same color as shown in FIG. 64, because only the generally U-shaped consecutive stripe phosphors 228 of white color exist in the way along the second direction D2. In FIG. 64, the hatched blocks show the propagation region of luminescence emitted from each unit luminescent area.
In this manner, the leakage of luminescence may color a pixel to be generally white, for example, by red because of red light leaked from the adjacent unit luminescent area EUP of the adjacent pixel. Namely, the leakage of luminescence from a pixel of the next line to a pixel of the previous line gives an adverse effect on the pixel of the previous line.
As described above, a conventional display device involves some problems due to the propagation and diffusion of ultraviolet rays:
Conventional Problem (1): While the self absorption and emission of ultraviolet rays are repeated, the excited Xe atoms may be ionized. In this case, a loss increases with the number of repetitions, which deteriorates luminous efficiency.
Conventional Problem (2): The ultraviolet rays may be absorbed by the protective layer 218 in the course of the phenomenon of the self absorption and emission of ultraviolet rays occurring along the barrier ribs 229 to thereby cause loss of ultraviolet rays. In this case, loss increases with increasing traveling distance of the phenomenon, which deteriorates luminous efficiency
The aforementioned conventional problems (1) and (2) are raised of the aspect of luminous efficiency. Further, from the viewpoint of the leakage of luminescence as described with reference to FIG. 64, the following other problems are presented.
Conventional Problem (3): Between pixels EG adjacent to each other with regard to the second direction D2, luminescence generated at each adjacent display line leaks into its adjacent unit luminescent area EUP of the same color This leakage of luminescence makes it difficult to hold a required pixel dimension and to achieve image display with required luminance at each of adjacent display lines, especially affecting color balance of a combination of primary colors to be used in a s standard color display.
Further, another problem comes up in manufacturing a high-resolution plasma display device so as to keep up with th e increase in pixel density.
Conventional Problem (4): When luminescence occurring at each unit luminescent area EUP extends over different unit luminescent areas of adjacent pixels as shown in FIG. 64, as a space between the adjacent display lines decreases, leakage of discharge tends to occur between the display lines (hereinafter referred to as discharge between cells) as schematically shown by circles with hatching in FIG. 65. This changes a stock of wall charges between cells where gas discharge occurred from its original state, hindering display operation. Further, unnecessary discharge may be caused or no display discharge may not be induced by the leakage of discharge associated with the achievement of high resolution.
Such influence of discharge between cells increases as increasing applied voltage in display operation or decreasing pitch between electrodes, which presents an obstacle to the increase in pixel density of PDP1.
A first aspect of the present invention is directed to a surface discharge type plasma display panel comprising: a first substrate; a second substrate facing the first substrate in parallel, which provides a plurality of discharge spaces filled with discharge gas therebetween; a dielectric which is arranged on an opposing surface of the first substrate to the second substrate, abuts on the plurality of discharge spaces, and has a surface storing first and second wall charges in accordance with each of the plurality of discharge spaces; a plurality of barrier ribs of a first type which are arranged in parallel with each other on an opposing surface of the second substrate to the first substrate and has portions which reflect light of a visible-light area, each of the plurality of barrier ribs of the first type comprising a first side surface portion, a second side surface portion opposite to the first side surface portion, and a first top portion led to the first and second side surface portions; a barrier rib of a second type arranged on the opposing surface of the second substrate and intersecting with the plurality of barrier ribs of the first type; and phosphors provided on the opposing surface of the second substrate sandwitched between adjacent barrier ribs out of the plurality of barrier ribs of the first type, on the first side surface portion of one of the adjacent barrier ribs of the first type, and on the second side surface portion of the other of the adjacent barrier ribs of the first type, the phosphors emitting visible light in accordance with ultraviolet rays caused by discharge between the first and second wall charges.
Preferably, in the surface discharge type plasma display panel according to a second aspect of the present invention, the barrier rib of the second type has a portion which reflects the light of the visible-light area.
Preferably, in the surface discharge type plasma display panel according to a third aspect of the present invention, the barrier rib of the second type comprises: a third side surface portion; a fourth side surface portion opposite to the third side surface portion; and a second top portion led to the third and fourth side surface portions. The phosphors are further provided on the third and fourth side surface portions of the barrier rib of the second type.
Preferably, in the surface discharge type plasma display panel according to a fourth aspect of the present invention, the first top portion of each of the plurality of barrier ribs of the first type is in contact with the dielectric; and the plurality of barrier ribs of the first type has a first height from the second substrate to the first top portion which is almost equal to a second height from the second substrate to the second top portion of the barrier rib of the second type.
Preferably, in the surface discharge type plasma display panel according to a fifth aspect of the present invention, the first top portion of each of the plurality of barrier ribs of the first type is in contact with the dielectric; and a second height from the second substrate to the second top portion of the barrier rib of the second type is smaller than a first height from the second substrate to the first top portion of each of the plurality of barrier ribs of the first type.
Preferably, in the surface discharge type plasma display panel according to a sixth aspect of the present invention, the phosphors are further provided on the second top portion of the barrier rib of the second type.
Preferably, in the surface discharge type plasma display panel according to a seventh aspect of the present invention, the second height is set on the basis of a correlation between luminance of display light emitted from the first substrate to the outside, and an exhaust conductance corresponding to a flow path of gas specified by the adjacent barrier ribs of the first type, the second top portion of the barrier rib of the second type, and the dielectric.
Preferably, in the surface discharge type plasma display panel according to an eighth aspect of the present invention, if a shape factor xcex2 determining the exhaust conductance is found by: xcex2=(axc2x7b)2/((a+b)xc2x7L), the shape factor xcex2 satisfies an inequality as follows: 1.5 Exe2x88x924 mm2xe2x89xa6xcex2 less than (Hmainxe2x88x92b)2/((Hmain+b)xc2x7L), where Hmain and Hsub are the first and second heights, respectively; L is a width of the barrier rib of the second type; b is a length of a first side of a quadrangle having the maximum area out of quadrangles inscribed in the flow path, on the side of the second top portion; and a is a length of a second side orthogonal to the first side, which is found by (Hmainxe2x88x92Hsub).
Preferably, in the surface discharge type plasma display panel according to a ninth aspect of the present invention, the second height is set on the basis of the minimum priming voltage at which priming discharge occur in all of the plurality of discharge spaces.
Preferably, in the surface discharge type plasma display panel according to a tenth aspect of the present invention, a discharge shape factor K is not less than 0.03 xcexcm/Torr, if the discharge shape factor K is found by K=(axc2x7b)/(pxc2x7L), where L is a width of the barrier rib of the second type; a is a difference of height found by (Hmainxe2x88x92Hsub) where Hmain and Hsub are the first and second heights, respectively; b is a gap between the first side surface portion of the one of the adjacent barrier ribs of the first type and the second side surface portion of the other of the adjacent barrier ribs of the first type; and p is pressure of the discharge gas.
Preferably, the surface discharge type plasma display panel according to an eleventh aspect of the present invention further comprises: a plurality of pairs of electrodes each consisting essentially of first and second display electrodes extending in parallel with each other along a first direction on the opposing surface of the first substrate and constituting a corresponding one of display lines, said plurality of pairs of electrodes covered by the dielectric. In the panel, the second substrate comprises a plurality of address electrodes each extending along a second direction orthogonal to the first direction and located between the adjacent barrier ribs of the first type; each of the plurality of discharge spaces is specified by a pair of electrodes out of the plurality of pairs of electrodes, and an address electrode arranged so as to be orthogonal to the pair of electrodes out of the plurality of address electrodes; each of the first and second display electrodes comprises a strip transparent conductive film, and a metal electrode provided on an area of an opposing surface of the strip transparent conductive film to the plurality of discharge spaces on the side of an adjacent display line out of the display lines; the barrier rib of the second type extends along the first direction; each of the plurality of barrier ribs of the first type extends along the second direction; the barrier rib of the second type is provided on a first area of the opposing surface of the second substrate, the first area facing the metal electrode of the first display electrode corresponding to a discharge space isolated from its adjacent discharge space by the barrier rib of the second type, out of the plurality of discharge spaces; and the third surface portion of the barrier rib of the second type is provided on a second area of the opposing surface of the second substrate, the second area facing the strip transparent conductive film of the first display electrode except where the metal electrode is formed.
Preferably, in the surface discharge type plasma display panel according to a twelfth aspect of the present invention, the barrier rib of the second type is provided on a third area of the opposing surface of the second substrate, the third area facing the metal electrode of the second display electrode corresponding to the adjacent discharge space; and the fourth side surface portion of the barrier rib of the second type is provided on a fourth area of the opposing surface of the second substrate, the fourth area facing the strip transparent conductive film of the second display electrode except where the metal electrode is formed.
Preferably, the surface discharge type plasma display panel according to a thirteenth aspect of the present invention, further comprises: a second barrier fib of the second type formed in parallel with the barrier rib of the second type, between the jth unit luminescent area corresponding to the jth discharge space counted from the ith unit luminescent area along the opposed first and second side surface portions, and the (j+1)th unit luminescent area corresponding to the (j+1)th discharge space, on the opposing surface of the second substrate, where the ith unit luminescent area is an unit luminescent area corresponding to any one of the plurality of discharge spaces sandwitched between the adjacent barrier ribs of the first type and isolated by the barrier rib of the second type.
Preferably, in the surface discharge type plasma display panel, according to a fourteenth aspect of the present invention, the phosphors are further provided on both side surface portions of the second barrier rib of the second type.
Preferably, the surface discharge type plasma display panel according to a fifteenth aspect of the present invention, further comprises a plurality of pairs of electrodes each consisting essentially of the first and second display electrodes extending in parallel with each other along a first direction on the opposing surface of the first substrate and constituting a corresponding one of display lines, said plurality of pairs of electrodes covered by the dielectric. In the panel, the second substrate comprises a plurality of address electrodes each extending along a second direction orthogonal to the first direction and located between the adjacent barrier ribs of the first type; each of the plurality of discharge spaces is specified by intersection of the plurality of pairs of electrodes and the plurality of address electrodes; the barrier rib of the second type has a plurality of barrier ribs; the plurality of barrier ribs extend along the first direction; each of the plurality of barrier ribs of the first type extends along the second direction; and each of the plurality of barrier ribs is provided for each of the plurality of discharge spaces.
Preferably, in the surface discharge type plasma display panel according to a sixteenth aspect of the present invention, the second substrate comprises a plurality of address electrodes each extending along a second direction and located between the adjacent barrier ribs of the first type; and the jth unit luminescent area corresponds to the (i+1)th unit luminescent area. The ith and (i+1)th unit luminescent areas are specified by: (a) a first display electrode, common to the ith and (i+1)th unit luminescent areas, extending along a first direction orthogonal to the second direction on the opposing surface of the first substrate, extending over the ith and (i+1)th unit luminescent areas, and covered by the dielectric; (b) a second display electrode extending across the ith unit luminescent area along the first direction on the opposing surface of the first substrate and covered by the dielectric, which constitutes one display line in pair with the first display electrode; (c) another second display electrode extending across the (i+1)th unit luminescent area along the first direction on the opposing surface of the first substrate and covered by the dielectric, which constitutes another display line in pair with the first display electrode; and (d) the plurality of address electrodes. Further, the barrier rib and second barrier rib of the second type both extend along the first direction; and each of the plurality of barrier ribs of the first type extends along the second direction.
Preferably, the surface discharge type plasma display panel according to a seventeenth aspect of the present invention, further comprises: a third barrier rib of the second type provided between the ith and (i+1)th unit luminescent areas on the opposing surface of the second substrate, wherein the phosphors are further provided on both side surface portions of the third barrier rib of the second type.
An eighteenth aspect of the present invention is directed to a plasma display device comprising: a first substrate: a second substrate facing the first substrate in parallel, which provides a plurality of discharge spaces filled with discharge gas therebetween; a plurality of pairs of electrodes each consisting essentially of first and second electrodes which extend in parallel with each other along a first direction on an opposing surface of the first substrate to the second substrate; a dielectric which is formed on the opposing surface of the first substrate, covers the plurality of pairs of electrodes, and has a surface storing first and second wall charges in accordance with each of the plurality of discharge spaces; a plurality of barrier ribs of a second type extending in parallel with each other along the first direction on an opposing surface of the second substrate to the first substrate; and a plurality of barrier ribs of a first type extending in parallel with each other along a second direction orthogonal to the first direction on the opposing surface of the second substrate to the first substrate, the plurality of barrier ribs of the first type intersecting with the plurality of barrier ribs of the second type; a plurality of phosphors each provided on an area of the opposing surface of the second substrate surrounded by adjacent barrier ribs of the plurality of barrier ribs of the first type and by adjacent barrier ribs of the second type, and on opposed side surface portions of at least one out of both of the adjacent barrier ribs of the first type and the adjacent barrier ribs of the second type, each of the plurality of phosphors having portions emitting visible light in accordance with ultraviolet rays caused by discharge between the first and second wall charges stored in the surface of the dielectric. In the device, the second substrate comprises a plurality of third electrodes extending in parallel with each other along the second direction and located between the adjacent barrier fibs of the first type, and each of the plurality of discharge spaces is specified by a pair of electrodes of the plurality of pairs of electrodes, and a third electrode orthogonal to the pair of electrode out of the plurality of third electrodes. The plasma display device further comprises: a drive control circuit having a plurality of drivers each connected to the first and second electrodes of the plurality of pairs of electrodes, and the plurality of third electrodes, and each generating and outputting a driving signal to be applied to its corresponding electrode.
A nineteenth aspect of the present invention is directed to a method of manufacturing a surface discharge type plasma display panel comprising steps of: (a) providing a second substrate which specifies a plurality of discharge spaces filled with discharge gas with a first substrate, and comprises a plurality of address electrodes extending along a second direction, and; (b) on the second substrate, forming a plurality of barrier ribs of a first type extending in parallel with each other at first intervals along the second direction so that each of the plurality of address electrodes is located between adjacent barrier ribs out of the plurality of barrier ribs of the first type, and a plurality of barrier ribs of a second type extending in parallel with each other at second intervals along a first direction orthogonal to the second direction so as to intersect with the plurality of barrier ribs of the first type; (c) adhering phosphors to an area of the second substrate sandwitched between adjacent barrier ribs out of the plurality of barrier ribs of the first type, a first side surface portion of one of the adjacent barrier ribs of the first type, and a second side surface portion of the other of the adjacent barrier ribs of the first type facing to the first side surface portion.
Preferably, in the method of manufacturing a surface discharge type plasma display panel according to a twentieth aspect of the present invention, the step (a) comprises a step of: (a-1) preparing a member utilized when a mask is generated, the mask comprising a reticulated pattern specified by the first and second intervals. In the step (b), the mask is made from the member, and the plurality of barrier ribs of the first type and the plurality of barrier ribs of the second type are formed at the same time on the basis of the mask.
Preferably, in the method of manufacturing a surface discharge type plasma display panel according to a twenty and first aspect of the present invention, the step (a-1) further comprises steps of: (a-1-2) preparing a glass paste; and (a-1-3) preparing a predetermined photosensitive film as the member, and the step (b) comprises steps of: (b-1) forming the glass paste of a predetermined thickness on the whole surface of the second substrate; and (b-2) sticking the photosensitive film on the surface of the glass paste to form a dry film resist comprising the reticulated pattern as the mask by lithography method, and continuing to bore a hole in the glass paste by sand blast method from an exposed surface of the glass paste through a reticulated aperture of the dry film resist until the hole reaches the second substrate.
Preferably, in the method of manufacturing a surface discharge type plasma display panel according to a twenty and second aspect of the present invention, the dry film resist comprises a first mask portion of a first mask width extending along the second direction, and a second mask portion of a second mask width extending along, the first direction so as to be orthogonal to the first mask portion, the first mask width is not less than the second mask width; and the first and second mask widths are set on the basis of the first and second intervals, respectively.
Preferably, in the method of manufacturing a surface discharge type plasma display panel according to a twenty and third aspect of the present invention, the step (a) further comprises steps of: (a-2) preparing a glass paste; and (a-3) preparing a photosensitive film of a predetermined thickness as the member, and the step (b) comprises steps of: (b-1) sticking the photosensitive film on the whole surface of the second substrate; (b-2) transferring the reticulated pattern to the photosensitive film by arranging a first mask comprising the reticulated pattern specified by the first and second intervals on the surface of the photosensitive film and by irradiating the photosensitive film with a predetermined light through the first mask to thereby expose the photosensitive film, and then developing the photosensitive film; and (b-3) coating the glass paste on the second substrate. by using the photosensitive film with reticulated pattern transferred as the mask, drying the glass paste, and then stripping the photosensitive film.
Preferably, in the method of manufacturing a surface discharge type plasma display panel according to a twenty and fourth aspect of the pre-sent invention, the step (a-1) comprises a step of preparing a first mask having mask widths each corresponding to the first and second intervals, and a second mask with a plurality of apertures extending along the first direction and having a width corresponding to the first intervals which are arranged at intervals corresponding to the width of the barrier ribs of the first type. The step (a) further comprises steps of: (a-2) preparing a glass paste; and (a-3) preparing a first photosensitive film of a first thickness and a second photosensitive film of a second thickness as the member, and the step (b) comprises steps of: (b-1) sticking the first photosensitive film on the whole surface of the second substrate; (b-2) transferring a pattern of the first mask corresponding to the reticulated pattern to the first photosensitive film by arranging the first mask on the surface of the first photosensitive film and by irradiating the first photosensitive film with a predetermined light through the first mask to thereby expose the first photosensitive film, and then developing the first photosensitive film; (b-3) sticking the second photosensitive film on the surface of the developed first photosensitive film; (b-4) transferring a pattern of the second mask to the second photosensitive film by arranging the second mask on the surface of the second photosensitive film and by irradiating the second photosensitive film with the predetermined light through the second mask to thereby expose the second photosensitive film, and then developing the second photosensitive film; and (b-5) drying the glass paste after coating the glass paste on the second substrate by using the first and second photosensitive films remaining after the step (b-4) as the mask, and then stripping the first and second photosensitive films, wherein the sum of the first. thickness and the second thickness corresponds to the height of the barrier ribs of the first type from the second substrate.
According to the first aspect of the present invention, since the barrier rib of the second type is formed to be orthogonal to the plurality of barrier ribs of the first type, the following effects {circle around (1)} and {circle around (2)} can be achieved in any discharge spaces emitting visible light of the same color and isolated from each other by the barrier rib of the second type:
{circle around (1)} In any discharge spaces, gas discharge between cells due to leakage of discharge can be reduced or completely suppressed. Namely, when atoms or molecules or the like in a discharge gas as the source of luminescence of ultraviolet rays, are excited by each gas discharge occurring in each of any discharge spaces and move forward the barrier rib of the second type, they can collide with the barrier rib of the second type, providing their kinetic energy with the barrier rib of the second type. This loss of energy causes the excited atoms or molecules or the like to return to their ground state. (a) When the barrier ribs of the first and second types are the same in height and their top portions are in contact with the surface of the dielectric, all of the excited atoms or molecules or the like can collide with the barrier rib of the second type while losing their energy, because their movement toward the adjacent discharge space is impeded by the barrier rib of the second type. As a result, the leakage of discharge is completely prevented between the discharge spaces isolated by the barrier rib of the second type. On the other hand, (b) when the height of the barrier ribs of the first type is larger than the height of the barrier rib of the second type, or when the barrier ribs of the first and second types are the same in height but their top portions are not in contact with the surface of the dielectric, the excited atoms or the like will try to go over the barrier rib of the second type to the adjacent discharge space. However, since many of the excited atoms or the like still collide with the barrier rib of the second type and lose their energy, the number of excited atoms making their way into the adjacent discharge space over the barrier rib of the second type can be remarkably reduced in comparison with the conventional device with no barrier rib of the second type. Thus, the barrier rib of the second type remarkably reduces the leakage of discharge between the adjacent discharge spaces.
{circle around (2)} Further, when discharge between cells to be the cause of the leakage of discharge is certainly reduced or completely suppressed, a pitch between electrodes can be reduced as well in any discharge spaces isolated by the barrier rib of the second type. This allows an increase in pixel density along the barrier rib of the second type. Thus, a high-resolution panel can be achieved by providing the barrier rib of the second type across the panel.
According to the second aspect of the present invention, leakage of luminescence or visible light from one discharge space to another can be completely suppressed or sufficiently reduced in any discharge spaces isolated by the barrier rib of the second type. This completely or sufficiently suppresses the influence on color balance of pixels along the barrier rib of the second type, and makes it possible to display a further clear image without making a color run while improving picture quality. Thus, a fine panel with high luminance and high picture quality can be achieved by providing the barrier rib of the second type across the panel.
Since each discharge space is surrounded by the first side surface portion of one of the adjacent barrier ribs of the first type, the second side surface portion of the other of the adjacent barrier ribs of the first type, and the third and fourth side surface portions of the barrier rib of the second type, according to the present invention, visible light occurring in each of unit luminescent areas of any discharge spaces is reflected not only at the first side surface portion of one of the adjacent barrier ribs of the first type and the second side surface portion of the other of the adjacent barrier ribs of the first type which surround the unit luminescent area, but also at the third and fourth side surface portions of the barrier rib of the second type. This remarkably increases the amount of visible light to be emitted toward an observer. Thus, (a) when the barrier ribs of the first and second types are the same in height and their top portions are in contact with the surface of the dielectric, traveling of visible light from one unit luminescent area to another can be certainly prevented by the reflection of visible light at the third and fourth side surface portions of the barrier rib of the second type. Further, (b) when the height of the barrier ribs of the first type is larger than the height of the barrier rib of the second type, or when the barrier ribs of the first and second types are the same in height but their top portions are not in contact with the surface of the dielectric, since much of visible light is reflected at the third and fourth side surface portions of the barrier rib of the second type, the traveling of visible light can be prevented with a high probability. This increases the amount of visible light to be emitted toward an observer while preventing or sufficiently reducing the influence of the leakage of luminescence from one unit luminescent area to another, thereby achieving a plasma display panel with high luminance.
According to the third aspect of the present invention, since the phosphors adhere not only to the first and second side surface portions of the barrier ribs of the first type but also to the third and fourth side surface portions of the barrier rib of the second type, the following two effects {circle around (1)} and {circle around (2)} can be achieved in the respective unit luminescent areas of any discharge spaces isolated from each other by the barrier rib of the second type:
{circle around (1)} Luminous efficiency in converting ultraviolet rays into visible light can be improved in comparison with the conventional device, which improves luminance.
Namely, in respective discharge spaces isolated from each other, since the phosphors adhere so as to make its longitudinal section, which is vertical to the first and second substrates, U-shaped, the area of the phosphors for receiving ultraviolet rays caused by discharge can be increased. This makes it possible to irradiate the phosphors more speedily with more ultraviolet rays before a loss of ultraviolet rays is increased by increase in repetitions of discharge or by absorption of ultraviolet rays into the dielectric with increase in the traveling distance of ultraviolet rays, thereby remarkably reducing the loss of ultraviolet rays.
{circle around (2)} Further, since the phosphors are provided so as to surround gas discharge, the leakage of visible light from one unit luminescent area to another can be sufficiently suppressed. Namely, since visible light emitted from the phosphor in one unit luminescent area is reflected not only by the first and second side surface portions, and the third and fourth side surface portions in the unit luminescent area, and the phosphors on the first and second side surface portions but also by the phosphors on the third and fourth side surface portions, more visible light can be propagated to an observer. This further reduces the amount of visible light to be leaked into other unit luminescent areas.
According to the fourth aspect of the present invention, since the first height of the barrier ribs of the first type is almost equal to the second height of the barrier rib of the second type, in any discharge spaces isolated from each other by the barrier rib of the second type, it becomes possible to achieve (a) high luminance by reduction of the loss of ultraviolet rays; (b) suppression of the leakage of luminescence; and (c) suppression of the leakage of discharge, while achieving the effect as obtained by providing the adjacent barrier ribs of the first type in the conventional technique.
According to the fifth aspect of the present invention, since the second height of the barrier rib of the second type is set to be smaller than the first height of the barrier ribs of the first type, in any discharge spaces isolated from each other by the barrier rib of the second type, it becomes possible to achieve the following two effects {circle around (1)} and {circle around (2)}, while achieving the effect as obtained by providing the adjacent barrier ribs of the first type in the conventional technique:
{circle around (1)} By stabilizing discharge operation while facilitating the exhaustion of each discharge space and the filling of discharge gas into each discharge space in manufacturing the plasma display panel; it becomes possible to achieve (a) high luminance by reduction of the loss of ultraviolet rays; (b) suppression of the leakage of luminescence; and (c) suppression of the leakage of discharge;
{circle around (2)} By stabilizing discharge operation while simultaneously and certainly inducing the priming discharge in each discharge space, it becomes possible to achieve (a) high luminance by reduction of the loss of ultraviolet rays; (b) suppression of the leakage of luminescence; and (c) suppression of the leakage of discharge.
According to the sixth aspect of the present invention, since the phosphors adhere to the second top portion of the barrier rib of the second type, in any discharge spaces isolated from each other by the barrier rib of the second type, it becomes possible to further improve: (a) high luminance by reduction of the loss of ultraviolet rays; and (b) suppression of the leakage of luminescence. This is because ultraviolet rays traveling into a gap between the second top portion of the barrier rib of the second type and the surface of the dielectric is absorbed by the phosphors on the second top portion, and visible light traveling into the gap is reflected from the surface of the phosphors on the second top portion to an observer.
According to the seventh aspect of the present invention, since the difference between the first and second heights is determined on the basis of the correlation between the exhaust conductance and the luminance of display light, in each discharge space isolated by the barrier rib of the second type, it becomes possible to achieve (a) high luminance by reduction of the loss of ultraviolet rays; (b) suppression of the leakage of luminescence; and (c) suppression of the leakage of discharge, as well as to (d) facilitate the exhaustion of each discharge space and the filling of discharge gas into each discharge space in manufacturing the plasma display panel.
According to the eighth aspect of the present invention, since the shape factor xcex2 is not less than 1.5 Exe2x88x924 mm2 and less than the value found by (Hmainxe2x88x92b)2/((Hmain+b)xc2x7L), in any discharge spaces isolated from each other by the barrier rib of the second type, it becomes possible to stabilize discharge operation while facilitating and making reliable the exhaustion of each discharge space and the filling of discharge gas into each discharge space in manufacturing the plasma display panel. Especially, the shape factor xcex2 closer to 1.5 Exe2x88x924 mm2 further stabilizes the discharge operation, which maximizes the effects: (a) high luminance by reduction of the loss of ultraviolet rays; (b) suppression of the leakage of luminescence; and (c) suppression of the leakage of discharge.
According to the ninth aspect of the present invention, since the difference between the first and second heights is determined on the basis of the minimum priming voltage at which the priming discharge occur in all of the plurality of discharge spaces, in any discharge spaces isolated from each other by the barrier rib of the second type, it becomes possible to achieve: (a) high luminance by reduction of the loss of ultraviolet rays; (b) suppression of the leakage of luminescence; and (c) suppression of the leakage of discharge by stabilizing the discharge operation in each discharge space, while simultaneously and certainly inducing the priming discharge in each discharge space.
According to the tenth aspect of the present invention, since the minimum priming voltage at which the priming discharge occur simultaneously and certainly in all of the discharge spaces can be optimized, in any discharge space isolated by the barrier rib of the second type, the following effects {circle around (1)} to {circle around (4)} can be achieved:
{circle around (1)} (a) Increase in dark luminance; (b) occurrence of discharge outside the display area of the panel; and (c) deterioration in insulation between terminals electrically connecting the panel and external driving circuits, caused by too high priming voltage can be certainly prevented from happening;
{circle around (2)} Deterioration in withstand-voltage capability of the external driving circuits in generating the priming voltage can be certainly prevented from happening;
{circle around (3)} The necessity of using an active element with especially high withstand voltage as an element of the external driving circuits in generating the priming voltage can be avoided, and the use of an active element with flexibility becomes available;
{circle around (4)} Deterioration in withstand-voltage capability of the dielectric can be certainly prevented from happening.
According to the eleventh aspect of the present invention, the third side surface portion of the barrier rib of the second type is provided on the second area of the opposing surface of the second substrate, the second area facing the strip transparent conductive film of the first display electrode except where the metal electrode is formed. This achieves the following two effects {circle around (1)} and {circle around (2)}:
{circle around (1)} In a discharge space isolated from its adjacent discharge space by the third side surface of the barrier rib of the second type out of any discharge spaces, it becomes possible to facilitate reduction of power consumption by suppressing gas discharge at the metal electrode of the first display electrode. This achieves a further efficient surface discharge type plasma display panel. Namely, in the discharge space between the barrier rib of the second type provided in the first area facing the metal electrode of the first display electrode and the portion of the dielectric facing the metal electrode, when the barrier ribs of the first and second types are the same in height and their top portions are in contact with the surface of the dielectric, all excited atoms or molecules and the like moving toward the adjacent discharge space can collide with the barrier rib of the second type to thereby lose their energy. This completely avoids occurrence of gas discharge which cannot contribute to the luminance occurring in the discharge space. On the other hand, when the barrier ribs of the first and second types are different in height, or when the barrier ribs of the first and second types are the same in height but their top portions are not in contact with the surface of the dielectric, most of excited atoms or molecules and the like moving toward the adjacent discharge space can still collide with the barrier rib of the second type, so that unnecessary occurrence of discharge can be reduced as compared with the case in the conventional technique.
{circle around (2)} In a discharge space isolated by the third side surface portion of the barrier rib of the second type out of any discharge spaces, since both of the third side surface portion and the phosphors adhering thereto more project over the discharge space, ultraviolet rays occurring in the discharge space between the opposing surface of the second substrate and the portion of the dielectric which face the strip transparent conductive film of the first display electrode except where the metal electrode is formed, can further speedily reach the phosphors on the third side surface portion and the barrier rib of the second type. This further increases the effects: (a) high luminance by reduction of the loss of ultraviolet rays; (b) suppression of the leakage of luminescence; and (c) suppression of the leakage of discharge.
According to the twelfth aspect of the present invention, the fourth side surface of the second barrier rib is provided on the fourth area of the opposing surface of the second substrate, the fourth area facing the strip transparent conductive film of the second display electrode except where the metal electrode is formed. This achieves the following two effects {circle around (1)} and {circle around (2)}:
{circle around (1)} In a discharge space isolated from its adjacent discharge space by the forth side surface of the barrier rib of the second type, it becomes possible to facilitate reduction of power consumption by suppressing gas discharge at the metal electrode of, the first display electrode. This achieves a further efficient surface discharge type plasma display panel. Namely, in the discharge space between the barrier rib of the second type provided on the first area facing the metal electrode of the first display electrode and the portion of the dielectric facing the metal electrode, (a) when the barrier ribs of the first and second types are the same in height and their top portions are in contact with the surface of the dielectric, all excited atoms or molecules or the like moving toward the adjacent discharge space can collide with the barrier rib of the second type to lose their energy. This completely avoids occurrence of discharge which cannot contribute to the luminance occurring in the discharge space. Further, (b) when the barrier ribs of the first and second types are different in height, or when the barrier ribs of the first and second types are the same in height but their top portions are not in contact with the surface of the dielectric, most of excited atoms or molecules or the like moving toward the adjacent discharge space can still collide with the barrier rib of the second type, so that unnecessary occurrence of discharge can be further reduced as compared with the case in the conventional technique.
{circle around (2)} In a discharge space isolated by the fourth side surface portion of the barrier rib of the second type, since both the fourth side surface portion and the phosphors adhering thereto more project over the discharge space, ultraviolet rays occurring in the discharge space between the opposing surface of the second substrate and the portion of the dielectric which face the strip transparent conductive film of the first display electrode except where the metal electrode is formed, can further speedily reach the phosphors on the third side surface portion and the barrier rib of the second type. This further increases the effects: (a) high luminance by reduction of the loss of ultraviolet rays; (b) suppression of the leakage of luminescence; and (c) suppression of the leakage of discharge:
According to the thirteenth aspect of the present invention, since the second barrier rib of the second type is further provided between the jth and (j+1)th unit luminescent areas, the effect as obtained in any unit luminescent area by providing the barrier rib of the second type, that is, reduction or complete prevention of the leakage of discharge, can be obtained as well in the jth and (j+1)th unit luminescent areas isolated by the second barrier rib of the second type.
According to the fourteenth aspect of the present invention, since the phosphors also adhere to the second barrier rib of the second type provided between the jth and (j+1)th unit luminescent areas, all the effects as obtained in any unit luminescent area by providing the barrier rib of the second type and adhering the phosphors thereon can be obtained as well in the jth and (j+1)th unit luminescent areas isolated by the second barrier rib of the second type.
According to the fifteenth aspect of the present invention, the same effect as obtained in the fourteenth aspect of the present invention can be obtained in an unit luminescent area of any pixel.
According to the sixteenth aspect of the present invention, since the first display electrode is common to an area including the unit luminescent areas of adjacent pixels of the same color, and-two barrier ribs of the second type are provided so as to be orthogonal to the adjacent barrier ribs of the first type. This achieves the following four effects {circle around (1)} to {circle around (4)}:
{circle around (1)} The first display electrode common to two pixels brings about high pixel density, thereby achieving high resolution.
{circle around (2)} The same effect as obtained in the fourteenth aspect of the present invention can be achieved in the area including the unit luminescent areas of adjacent pixels of the same color.
{circle around (3)} The first display electrode common to two pixels excludes the influence of discharge occurring between the adjacent first and second display electrodes on each unit luminescent area of adjacent pixels of the same color.
{circle around (4)} The barrier rib of the second type provided only for every two pixels along the second direction permits an increase in alignment margin in sticking the first and second substrates together.
According to the seventeenth aspect of the present invention, since the third barrier rib of the second type is provided on the second substrate between the ith and (i+1)th unit luminescent areas, besides the effects {circle around (1)} to {circle around (3)} of the sixteenth aspect, the following(Y effect can be further achieved:
{circle around (4)} The leakage of discharge occurring between the common first display electrode and the second display electrode of further adjacent pixel can be completely or sufficiently reduced.
According to the eighteenth aspect of the present invention, it becomes possible to achieve the surface discharge plasma display device achieving the effects as obtained in the surface discharge type plasma display panel, described in the eleventh, twelfth, and fifteenth to seventeenth aspects of the present invention.
According to the nineteenth aspect of the present invention, it is possible to achieve the second substrate with the phosphors adhering to each box-shaped discharge space surrounded by two adjacent barrier ribs of the first type and two adjacent barrier ribs of the second type. This allows the surface discharge type plasma display panel to achieve: (a) high luminance by reduction of the loss of ultraviolet rays; (o) suppression of the leakage of luminescence; and (c) suppression of the leakage of discharge.
According to the twentieth aspect of the present invention, a plurality of barrier ribs of the first type and a plurality of barrier ribs of the second type can be easily formed at the same time on the basis of a mask comprising a reticulated pattern.
According to the twenty-first aspect of the present invention, the barrier ribs of the first and second types of the same height can be formed at the same time by using the conventional sand blast method as it is.
According to the twenty-second aspect of the present invention, the barrier ribs of the first type and the barrier ribs of the second type smaller in height than the barrier ribs of the first type can be formed at the same time by using the conventional sand blast method as it is.
According to the twenty-third and twenty-forth aspects of the present invention, fine barrier ribs of the first and second types can be accurately formed at the same time without rounding their edge portions and making large fluctuation in height.
The present invention is made to solve the problems of the conventional device, pursuing the following objects:
An object of the present invention is to increase luminous efficiency.
Another object of the present invention is to improve luminance so as to maintain an original color balance, while reducing or completely preventing the leakage of luminescence.
A further object of the present invention is to increase the applied voltage in the display operation, and to stabilize display operation with increasing pixel density by reducing or completely preventing the gas discharge between cells.
To achieve the aforementioned objects, the present invention has proposed the second substrate having a new structure.
The present invention has further proposed the manufacturing method of a plasma display panel (PDP) with such characteristics.
These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.